This invention relates to a hinge assembly which is suited to be used for a foldable cellular telephone or the like.
In general, a foldable cellular telephone includes, as shown in FIGS. 18 and 19, a transmission section A and a reception section B. The transmission section A and the reception section B are turnably connected through a hinge assembly (not shown) for turning between a non-talk position where the transmission section A and the reception section B are abutted with each other as indicated by a solid line of FIG. 18 and a talk position as indicated by a solid line of FIG. 19. Moreover, when the angle formed between the transmission section A and the reception section B is smaller than xcex1, the transmission section A and the reception section B are turned into a non-talk position by bias means built in the hinge assembly and held in that position. When the angle formed between the transmission section A and the reception section B is brought to be larger than a predetermined angle xcex2, the transmission section A and the reception section B are turned into the talk position by bias means and held in that position.
As shown in FIG. 20, the hinge assembly includes a pair of abutment plates (abutment members) C,D arranged in mutually opposing relation and bias means (not shown) for biasing the paired abutment plates C,D towards each other. The pair abutment plates C,D are non-turnably connected to the transmission section A and the reception section B, respectively. Therefore, the abutment plates C,D are relatively turned as the transmission section A and the reception section B are turned.
The abutment plate C has a pair of projections C1, C1 which are formed on its opposing surface with respect to the abutment plate D and which are arranged 180 degrees away from each other in the circumferential direction. The remaining abutment plate D also has a pair of recesses D1, D1, which are formed on its opposing surface with respect to the abutment plate C and which are arranged 180 degrees away from each other in the circumferential direction. The projection C1 and the recess D1 retain the transmission section A and the reception section B in a non-talk position or in a talk position with the help of the biasing force of the bias means.
Specifically, as shown in FIG. 21, the projection C1 and the recess D1 are arcuate in section. When the transmission section A and the reception section B are in the non-talk position, the projection C1 and the recess D1 are, as shown in FIG. 21(A), abutted with each other at areas which are slightly circumferentially away from their centers. Owing to this arrangement, the biasing force of the bias means is converted into a rotational biasing force (rotation biasing force for turning the abutment plate D in a direction opposite to the arrowed direction) for turning the abutment plate C in the arrowed direction. By this rotational biasing force, the transmission section A and the reception section B are held in the non-talk position. As shown in FIG. 21(B), when the angle formed between the transmission section A and the reception section B is xcex1 or less, an area which is slightly away from the central part of the projection C1 contact one end portion of the recess D1. By this, the abutment plate C is biased in the arrowed direction of FIG. 21(B) and the transmission section A an the reception section B are turned in the non-talk position. When the angle formed between the transmission section A and the reception section B is xcex2 or more, the projection C1 and the recess D1 are brought into a symmetrical state with respect to the state shown in FIG. 21(B). Accordingly, the abutment plate C is biased in a direction opposite to the arrowed direction and the transmission section A and the reception section B are turned as far as to the talk position. When the transmission section A and the reception section B are located in the talk position, the projection C1 and the recess D1 are press-contacted at their central areas with each other as shown in FIG. 21(C). In that connection, the biasing force of the bias means merely urges the projection C1 against the bottom surface of the recess D1 and is never converted into a rotational biasing force. However, when the abutment members C,D are turned into either one direction from the position (hereinafter referred to as the xe2x80x9cneutral positionxe2x80x9d) shown in FIG. 21(C), the biasing force of the bias means is converted into a rotational biasing force and causes the abutment members C,D to return into the neutral position. Accordingly, the transmission section A and the reception section B are held in the talk position.
As shown in FIGS. 22 and 23, when viewed in the direction of the axes of the abutment plates C, D, although the projection C1 exhibits a generally rectangular configuration, the recess D1 exhibits a rectangular configuration in the example shown in FIG. 22 but the recess D1 exhibits a sector-like configuration in the example shown in FIG. 23. When the abutment plates C, D are located in the neutral position, the projection C1 and the recess D1 are line contacted with each other at their central areas in any one of the above-mentioned two configurations of the recess D1. However, when the abutment plates C, D are relatively turned away from the neutral position in a range of an angle xcex1, the projection C1 contacts the recess D1 only at its outer periphery side in case the recess D1 is in rectangular configuration and it contacts the recess D1 only at its inner periphery side in case the recess D1 is in sector-like configuration. Accordingly, the conventional hinge assembly, there is such a problem that the projection C1 is worn off soon.
In order to solve the above problem, the features of the present invention reside in a hinge assembly comprising a pair of abutment members arranged in mutually opposing relation and capable of making relative rotation, and bias means for biasing the pair of abutment members, so as to be press contacted with each other, one of the pair of abutment members having a projection formed on an opposing surface thereof and extending radially of the abutment member, the other abutment member having a recess formed on an opposing surface thereof and allowing the projection to be brought therein and thereout in accordance with the relative rotation of the their abutment members,
the hinge assembly being characterized in that the recess comprises an inner recess at an inner side and an outer recess at an outer side in a radial direction of the abutment member, and
one side surface of the inner recess is parallel to a radial line of the abutment member and one side surface of the outer recess is slanted with respect to one side surface of the inner recess such that an inner end portion thereof is crossed with an outer end portion of one side surface of the inner recess and an outer end portion thereof is away from the inner recess in a circumferential direction towards outside in the radial direction of the abutment member, so that one side surfaces of the inner and our recesses which contact one end portion of the projection, when viewed in a direction of axes of the abutment members, exhibit a dogleg like configuration as a whole.
It is preferred that one side surface of the outer recess is arranged such that one end portion of the one side surface of the outer recess in the circumferential direction of the abutment member contacts an opposing surface of the abutment member.
It is also preferred that one side surfaces of the inner recess and the outer recess are defined by an outwardly projecting arcuate surface.
It is also preferred that the inner recess and the outer recess, when viewed in an axial line of the fixed disc, are in symmetric relation with respect to a center line passing through width-wise centers of the inner recess and the outer recess and orthogonal to the axis of the abutment member.
It is also preferred that when the pair of abutment members are turned into a predetermined neutral position, the projection comes into contact with opposite side portions of the inner recess.